Severe explosive psoriasis and/or Reiter's syndrome may be an early cutaneous manifestation of HIV infection with a poor prognosis for development of AIDS - the acquired immunodeficiency syndrome. The association between psoriasis and HIV infection suggests an immunologic basis and possibly an infectious basis for the pathogenesis of psoriasis. Zidovudine therapy rapidly clears psoriasis and offers an important clinical model for understanding psoriasis and its observed association with AIDS. Akin biopsies and peripheral lymphocytes from HIV+ and HIV- psoriatics before and after zidovudine therapy will be studied for immunologic cell populations, DR antigen, and cytokine expression, and HIV infection using double immunoperoxidase and immunofluorescence antibodies, and riboprobes and 35S-UTP labeled riboprobe for in situ hybridization. HLA antigen associations in AIDS/psoriasis will be explored using Southern blotting to DR, DQ, and C locus cDNA probes. Analysis of AIDS associated psoriasis and the zidovudine induced remission at the molecular level should lead to a better understanding of the pathogenesis of psoriasis, its association with HIV infection, and better, safer therapy for psoriasis in general.